Shark deterrents need testing: scientist

Shark deterrents are not always effective and independent testing of them should be required by law, a WA researcher says, amid the political debate on sharks after a fatal attack on a teenager in the state's south.

Laeticia Brouwer, 17, died on Monday after being bitten by a shark while surfing in Esperance, and the state government says it will subsidise 1000 shark deterrent devices instead of deploying drum lines or culling the animal.

University of Western Australia shark researcher Shaun Collin says "culling is not the answer", and instead wants the independent testing of any shark deterrent to be legally required.

He says many devices have not been tested, or test results are not available to the public.

UWA has led "very extensive" testing of the Shark Shield Freedom7, which is worn on the ankle and emits electronic pulses to deter sharks.

The device was tested in over 400 interactions with great white sharks in South Africa, and was found to not always be effective as sharks attack in various ways.

"No deterrent device currently on the market, or in the future, is likely to provide 100 per cent protection," Professor Collin said.

The electric field released by the Shark Shield Freedom7 extends to about 2-3 metres, but was found to be most effective when sharks were about 0.8-1.3 metres away and not attacking from below.

Prof Collin said sharks can swim up to 35-40km/h when attacking from below, in an "ambush"attack, such as when they mistake a dark silhouette for prey, and this speed would prevent the device from working.

"Understanding their sensory needs and how they target prey is the secret to truly evolving the most effective deterrent

"The combination of both lights and sounds, together, may provide a better deterrent effect."

WA Fisheries Minister Dave Kelly says the government's policy response will soon be released, after federal Environment Minister Josh Frydenberg said he would be open to any policies to prevent further attacks.

Mr Kelly has opposed the use of drum lines and a shark cull after Monday's fatal attack.

"Deploying drum lines after an attack simply don't make our beaches any safer," he told reporters on Wednesday.

Prof Collin said the WA coast was part of the great white's migration route and education on shark behaviour was vital.

"Esperance is effectively a thoroughfare for great whites that move along the southern ocean, and move up the WA coast.